A case report of atrial fibrillation in early adulthood: dig deeper.

Background: Atrial fibrillation (AF) is a common cardiac arrhythmia, which is often associated with underlying risk factors and undiagnosed conditions, including congenital heart disease. Atrial septal defects (ASDs) come to mind, albeit arrhythmias usually present later in life. We present herewith a young patient with cor triatriatum sinister (CTS), with some delay in establishing the diagnosis, following new onset AF in early adulthood. Case summary: A 31-year-old man presented with pre-syncope and coryzal symptoms and was newly diagnosed with AF in the context of an intercurrent viral illness. After treatment with oral anticoagulation and successful outpatient cardioversion, he was discharged from cardiology review. Two years later he re-presented with exercise intolerance and a 12-lead electrocardiogram revealing recurrence of AF. Subsequent investigation with transthoracic echocardiography revealed the underlying congenital cardiac defect of CTS, together with an ASD and patent foramen ovale. After corrective surgery, which involved membrane resection, a Cox-maze procedure and ASD closure, sinus rhythm was restored and at follow-up the patient had returned to baseline function. Discussion: Young patients presenting with new onset AF should undergo thorough cardiovascular assessment to identify treatable causes and reversible risk factors. Cor triatriatum sinister is a rare congenital anomaly that may present in adulthood and give rise to symptomatic AF. Surgical correction including a Cox-maze procedure in our patient resulted in restoration of sinus rhythm and a return of the patient's baseline functional status and improved quality of life.